Electrical equipment



, 17, 1967 N. L. DRIEMEYER 3,299,208

ELECTRICAL EQUIPMENT Filed April 29, 1.963

INVENTOR. NORMAN L. DRIEIMEYER United States Patent 3,299,208 ELECTRICAL EQUIPMENT Norman L. Driemeyer, 5760A Saloma, St. Louis, Mo. 63120 Filed Apr. 29, 1963, Ser. No. 276,577 7 Claims. (Cl. 179-13) This invention relates to improvements in sound-reproducing equipment. More particularly, this invention relates to improvements in sound-reproducing devices that are usable with monaural sound-reproducing devices.

It is, therefore, an object of the present invention to provide an improved sound-reproducing device that is usable with a monaural sound-reproducing device.

Records and tapes can be made so they can record stereophonic sound; and sound-reproducing devices are available which can substantially faithfully reproduce stereophonic sound from stereophonic records and tapes. Unfortunately, sound-reproducing devices that substantially faithfully reproduce stereophonic sound from stereophonic tapes and records are expensive. Also, stereophonic records and tapes are expensive. It would be desirable to provide a sound-reproducing device which was inexpensive but which could be used with a monaural sound-reproducing device and monaural records or tapes to simulate substantially faithful reproduction of stereophonic sound. The present invention provides such a sound-reproducing device; and it is, therefore, an object of the present invention to provide a sound-reproducing device which is inexpensive but which can be used with a monaural sound-reproducing device and monaural records or tapes to simulate substantially faithful reproduction of stereophonic sound.

Stereophonic sound-reproducing devices usually are able to substantially faithfully reproduce stereophonic sound, from stereophonic records or tapes, at just one small area in a room. This means that just a few persons in a room can hear the substantially faithful reproduction of the stereophonic sound. It would be desirable to provide a sound-reproducing device which could simulate substantially faithful reproduction of stereophonic sound and which could enable many persons in a room to hear the simulated substantially faithful reproduction of stereophonic sound. The present invention provides such a sound-reproducing device; and it is, therefore, an object of the present invention to provide a sound-reproducing device which can simulate substantially faithful reproduction of stereophonic sound and which can enable many persons in a room to hear the simulated substantially faithful reproduction of stereophonic sound.

The sound-reproducing device provided by the present invention can be used with stereophonic as well as monaural sound-reproducing devices. Where that sound-reproducing device is used with a monaural sound-reproducing device which uses monaural records or tapes, that sound-reproducing device simulates substantially faithful reproduction of stereophonic sound. Where that soundreproducing device is used with a stereophonic soundreproducing device which uses stereophonic records or tapes, that sound-reproducing device provides substantially faithful reproduction of stereophonic sound and makes that substantially faithful reproduction of stereophonic sound available to many persons in a room. It is, therefore, an object of the present invention to provide a sound-reproducing device which can be used with stereophonic as well as monaural sound-reproducing devices.

Other and further objects and advantages of the present invention should become apparent from an examination of the drawing and accompanying description.

In the drawing and accompanying description a preferred embodiment of the present invention is shown and 0 speaker can be mounted adjacent the opposite side or opposite end of that room. One terminal of the sound-reproducingdevic'e provided by the present invention is denoted by the numeral 14; and that terminal is connected to one terminal of the speaker 10 by a junction 17 and a conductor 18. That terminal also is connected to one 7 terminal of the speaker 12 by the junction 17 and a conductor 19. A second terminal of the sound-reproducing device provided by the present invention is denoted by the numeral 16; and a third terminal of that sound-reproducing device is denoted by the numeral 15. A jumper 11 is shown connected across the terminals 15 and 16 by junctions 43 and 45; but, whenever desired, that jumper can be removed.

Whenever the sound-reproducing device provided by the present invention is to be used with a monaural sound-reproducing device that uses monaural records or tapes, the jumper 11 will be secured to the junctions 43 and 45; and the terminals 14 and 16 will be connected to the two leads extending from the amplifier of the said monaural soundreproducing device. Whenever the sound-reproducing device provided by the present invention is to be used with a stereophonic sound-reproducing device that uses stereophonic records or tapes, the jumper 11 will be separated from one or the other or both of the junctions 43 and 45; and the terminal 14 will be connected to the common lead extending from the amplifier of the said stereophonic sound-reproducing device, while the terminals 15 and 16 will be connected to the other two leads extending from the amplifier of the said stereophonic sound-reproducing device.

The other terminal of the speaker 10 is connected to a movable con-tact 26 by a conductor 20, a junction 22, and a capacitor 24. That other terminal is also connected to a stationary contact 40 by the conductor 20, the junction 22, a resistor 28, a junction 30, parallel-connected resistor 34, inductor 36 and capacitor 38, and junction 32. A movable contact 42 is mounted adjacent the stationary contact 40; and the movable contact 42 is connected to the terminal 15 by the junction 45. A movable contact 44 is mounted adjacent the movable contact 26; and the movable contact 44 also is connected to the terminal 15 by the junction 45. The movable contacts 42 and 44 are supported on an elongated contact blade; and that contact blade biases the movable contact 42 toward the stationary contact 40 and also biases the movable contact 44 toward the movable contact 26. When the movable contact 26 is in its un-stressed position, that movable contact will be spaced a short distance from the movable contact 44; and the movable contact 42 will be in engagement with the stationary contact 40.

The other terminal of the speaker 12 is connected to a movable contact 52 by a conductor 46, a junction 48, and a capacitor 50. That other terminal of that speaker also is connected to a stationary contact 66 by the conductor 46, the junction 48, a resistor 54, a junction 56, parallelconnected resistor 60, inductor 62 and capacitor 64, and a junction 58. A movable contact 68 is mounted adjacent the stationary contact 66; and that movable contact is connected to the terminal 16 by the junction 43. A movable contact 70 is mounted adjacent the movable contact 52; and the movable contact 70 is connected to the termi- 3 nal 16 by the junction 43. The movable contacts 68 and 70 are mounted on an elongated contact blade; and that contact blade biases the movable contact 68 toward the stationary contact 66 while also biasing the movable contact 70 toward the movable contact 52. When the movable contact 52 is in its un-stressed position, that movable contact Will be spaced away from the movable contact 70; and the movable contact 68 will be in engagement with the stationary contact 66.

The numeral 72 denotes a small electric motor which has a cam 74 mounted on the output shaft thereof. That shaft has a high dwell with an angular extent of slightly greater than one hundred and eighty degrees. That cam also has a low dwell with an angular extent of slightly less than one hundred and eighty degrees.

Whenever the low dwell of the cam 74 is in register with the movable contact 52, that movable contact Will be in its un-stressed position; and this means that the contacts 52 and 70 will be spaced apart and that the contacts 66 and 68 will be in engagement with each other. Whenever the high dwell of the cam 74 engages the movable contact 52, that movable contact will be moved into engagement with the movable contact 70 and the movable contact 68 will be moved out of engagement with the stationary contact 66. Whenever the low dwell of the cam 74 is in register with the movable contact 26, that movable contact will be in its un-stressed position; and this means that the contacts 26 and 44 will be spaced apart and that the contacts 40 and 42 will be in engagement with each other. Whenever the high dwell of the cam 74 engages the movable contact 26, that movable contact will be moved into engagement with the movable contact 44 and the movable contact 42 will be moved out of engagement with the stationary contact 40.

In one preferred embodiment of the present invention, each of the resistors 28 and 54 had a resistance value of fifteen ohms, each of the resistors 34 and 60 had a resistance value of fifty-six ohms, each of the inductors 36 and 62 had an inductance value of six and two tenths microhenries, each of the capacitors 38 and 64 had a capacitance value of one microfarad, and each of the capacitors 24 and 50 had a capacitance value of twentyfive microfarads. The capacitors 24 and 50 will readily pass electrical signals corresponding to high frequency sounds but will appreciably attenuate electrical signals corresponding to low frequency sounds. The parallelconnected resistor 34, inductor 36 and capacitor 38 will readily pass electrical signals corresponding to low frequency sounds, but will appreciably attenuate electrical signals corresponding to high frequency sounds; and the parallel-connected resistor 60, inductor 62 and capacitor 64 will readily pass electrical signals corresponding to low frequency sounds but will appreciably attenuate electrical signals corresponding to high frequency sounds. The parallel-connected inductor 36, capacitor 38 and resistor 34 will act as a low Q tuned circuit; and, similarly, the parallel-connected inductor 62, capacitor 64 and resistor 60 will act as a low Q tuned circuit.

When the terminals 14 and 16 of the sound-reproducing device provided by the present invention are connected to the two leads extending from the amplifier of a monaural sound-reproducing device, and when the terminals of the motor 72 are connected to a suitable source of power, signals will flow from the terminals 14 and 16 to the speakers and 12. When the cam 74 is in the position shown by the drawing, some of the signals will flow from the terminal 14 via junction 17, conductor 18, speaker 10, conductor 20, junction 22, capacitor 24, movable contacts 26 and 44, junction 45, jumper 11, and junction 43 to the terminal 16. Other of the signals will flow from terminal 14 via junction 17, conductor 19, speaker 12, conductor 46, junction 48, resistor 54, junction 56, parallel-connected resistor 60, inductor 62 and capacitor 64, junction 58, stationary contact 66, movable contact 68, and junction 43 to the terminal 16. This means that those signals which correspond to the high frequency sounds will be supplied to the speaker .10 without appreciable attenuation but will be supplied to the speaker 12 in attenuated form. Conversely, those signals which correspond to the low frequency sounds will be supplied to the speaker 10 in attenuated form but will be supplied to the speaker 12 without appreciable attenuation. Consequently, the sound issuing from the speaker 10 will have a higher proportion of high frequency sounds than will the sound issuing from the speaker 12; and the sound issuing from the speaker 12 will have a higher proportion of low frequency sounds than will the sound issuing from the speaker '10.

As the high dwel-l of the cam 74 engages the movable contact 52, that movable contact will be moved into engagement with the movable contact 70; and, almost immediately thereafter, the movable contact 68 will be moved out of engagement with the stationary contact 66.

. At this time, and for a few further degrees of revolution of the output shaft of the motor 72, the movable contacts 26 and 44 will remain in engagement with each other and the movable contact 42 will remain out of engagement with the stationary contact 40. This means that some of the signals which are supplied to the terminals 14 and 16 will continue to pass through the speaker 10 and the capacitor 24, but that the rest of those signals will pass through the speaker 12 and the capacitor 50 rather than through that speaker and the parallel-connected resistor 60, inductor 62 and capacitor 64. All of this means that for the short period of time when the high dwell of the cam 74 is holding both the movable contacts 26 and 52 in their stressed positions, the signals corresponding to the high frequency sounds will be supplied to both of the speakers 10 and 12 without appreciable attenuation, while the signals which correspond to the low frequency sounds and which are supplied to both of those speakers will be attenuated.

As the cam 74 continues to rotate, the high dwell thereon will move out of engagement with the movable contact 26 and the low dwell thereon will move into register with that movable contact. Thereupon, the movable contact 26 will move to its un-stressed position; and at such time the movable contact 26 will be out of engagement with the moveable contact 44 and the movable contact 42 will be in engagement with the stationary contact 42. This means that some of the signals applied to the terminal 14 will flow via junction 71, conductor '18, speaker 10, conductor 20, junction 22, resistor 28, junction 30, parallel-connected resistor 34, inductor 36 and capacitor 38, junction 32, stationary contact 40, movable contact 42, junction 45, jumper 11, and junction 43 to the terminal 16. Other signals will flow from terminal 14 via junction 17, conductor 19, speaker 12, conductor 46, junction 48, capacitor 50, movable contacts 52 and 70, and junction 43 to the terminal 16. This means that the signals which correspond to the high frequency sounds will be supplied to the speaker 10 in attenuated form but will be supplied to the speaker 12 without appreciable attenuation; and that the signals which correspond to the low frequency sounds will be supplied to the speaker 10 without appreciable attenuation but will be supplied to the speaker 12 in attenuated form. As a result, the sound issuing from the speaker 10' will have a higher proportion of low frequency sounds than will the sound issuing from the speaker 12; and it also means that the sound issuing from the speaker 12 will have a higher proportion of high frequency sounds than will the sound issuing from the speaker 10.

As the high dwell of the cam 74 again engages the movable contact 26, that contact will again engage the movable contact 44; and the movable contact 42 will again move out of engagement with the stationary contact 40. At this time, and for a few further degrees of revolution of the output shaft of the motor 72, the movable contacts 52 and 70 will remain in engagement with each other and the movable contact 68 will remain out of engagement with the stationary contact 66-. This means that some of the signals which are supplied to the terminals 14 and 16 will continue to pass through the speaker 12 and the capacitor 50, but that the rest of those signals will pass through the speaker and the capacitor 24 rather than through that speaker and the parallel-connected resistor 34, inductor 36 and capacitor 38. All of this means that for this further short period of time when the high dwell of the cam 74 is holding both of the movable contacts 26 and 52 in their stressed positions, the signals corresponding to the high frequency sounds will be supplied to both of the speakers 10 and 12 without appreciable attenuation, while the signals which correspond to the low frequency sounds and which are supplied to both of those speakers will be attenuated.

As the cam 74 continues to rotate, the high dwell thereon will move out of engagement with the movable contact 52 and the low dwell thereon will move into register with that movable contact. Thereupon, the movable contact 52 will move to its un-stressed position; and at such time the movable contact 52 will be out of engagement with the movable contact 76 and the movable contact 63 will be in engagement with the stationary contact 66. Consequently, the sound issuing from the speaker 10 will again have a higher proportion of high frequency sounds than will the sound issuing from the speaker 12; and the sound issuing from the speaker 12 will again have a higher proportion of low frequency sounds than will the sound issuing from the speaker 10.

It will thus be apparent that for about one-half of each revolution of the output shaft of the motor '72, the sound issuing from the speaker 10 will have a high proportion of high frequency sounds and will have a low proportion of low frequency sounds while the sound issuing from the speaker 12 will have a low proportion of high frequency sounds and will have a high proportion of low frequency sounds. For about the other one-half of each revolution of the output shaft of the motor 72, the sound issuing from the speaker 16 will have a low proportion of high frequency sounds and will have a high proportion of low frequency sounds while the sound issuing from the speaker 12 will have a high proportion of high frequency sounds and will have a low proportion of low frequency sounds. This means that during each revolution of the out-put shaft of the motor 72, the proportions of high frequency sounds and low frequency sounds will recurrently shift between the speakers 10 and 12; and this shifting produces an audible effect which closely simulates substantially faithfully reproduced stereophonic sound.

In one preferred embodiment of the present invention, the output shaft of the motor 72 will make two revolutions each minute. This means that the proportions of high frequency sounds and the proportions of low frequency sounds will shift about every fifteen seconds. Such an arrangement provides an attractive and pleasant effect upon the listeners. q

Where desired, the motor 72 could be a variable speed motor. With such a motor, the time intervals between the stressing and releasing of the movable contacts 26 and 52 could be varied at will.

When the terminal 14 is connected to the common lead extending from the amplifier of a stereophonic sound-reproducing device and the terminals 15 and 16 are connected to the other two leads extending from that amplifier, when the terminals of the motor are connected to a suitable source of power, and when the jumper 11 is removed, signals will fiow to the speakers 10 and 12. When the cam 74 is in the position shown by the drawing, some of the signals will flow from the terminal 14 via junction 17, conductor 18, speaker 10, conductor 20, junction 22, capacitor 24, movable contacts 26 and 44, and junction 45 to the terminal 15. Other of the signals will flow from terminal 14 via junction 17, conductor 19, speaker 12, conductor 46, junction 48, resistor 54, junction 56,

parallel-connected resistor 60, inductor 62 and capacitor 64, junction 58, stationary contact 66, movable contact 68, and junction 43 to the terminal 16. This means that those signals which correspond to the high frequency sounds will be supplied to the speaker 10 without appreciable attenuation but will be supplied to the speaker 12 in attenuated form. Conversely, those signals which correspond to the low frequency sounds will be supplied to the speaker 10 in attenuated form but will be supplied to the speaker 12 without appreciable attenuation. Consequently, the sound issuing from the speaker 10 will have a higher proportion of high frequency sounds than will the sound issuing from the speaker 12; and the sound issuing from the speaker 12 will have a higher proportion of low frequency sounds than will the sound issuing from the speaker 10.

As the high dwell of the cam 74 engages the movable contact 52, that movable contact will be moved into engagement with the movable contact 70; and, almost immediately thereafter, the movable contact 68 will be moved out of engagement with the stationary contact 66. At this time, and for a few further degrees of revolution of the output shaft of the motor 72, the movable contacts 26 and 24 will remain in engagement with each other and the movable contact 42 will remain out of engagement with the stationary contact 40. This means that some of the signals which are supplied to the terminals 14, 15 and 16 will continue to pass through the speaker 10 and the capacitor 24, but that the rest of those signals will pass through the speaker 12 and the capacitor 50 rather than through that speaker and the parallelconnected resistor 60, inductor 62 and capacitor 64. All of this means that for the short period of time when the high dwell of the cam 74 is holding both of the movable contacts 26 and 52 in their stressed positions, the signals corresponding to the high frequency sounds will be supplied to both of the speakers 10 and 12 without appreciable attenuation, while the signals which correspond to the low frequency sounds and which are supplied to both of those speakers will be attenuated,

As the cam 74 continues to rotate, the high dwell thereon will move out of engagement with the movable contact 26 and the low dwell thereon will move into register with that movable contact. Thereupon, the movable contact 26 will move to its un-stressed position; and at such time the movable contact 26 will be out of engagement with the movable contact 44 and the movable contact 42 will be in engagement with the stationary contact 42. This means that some of the signals applied to the terminal 14 will flow via junction 17, conductor 18, speaker 10, conductor 20, junction 22, resistor 28, junction 30, parallel-connected resistor 34, inductor 36 and capacitor 38, junction 32, stationary contact 46, movable contact 42, junction 45, and terminal 15. Other signals will flow from terminal 14 via junction 17, conductor 19, speaker 12, conductor 46, junction 48, capacitor 50, movable contacts 52 and 70, and junction 43 to the tertminal 16. This means that the signals which correspond to the high frequency sounds will be supplied to the speaker 10 in attenuated form but will be supplied to the speaker 12 without appreciable attenuation; and that the signals which correspond to the low frequency sounds will 'be supplied to the speaker 16 without appreciable attenuation but will be supplied to the speaker 12 in attenuated form. As a result, the sound issuing from the speaker 10 will have a higher proportion of low frequency sounds than will the sound issuing from the speaker 12; and it also means that the sound issuing from the speaker 12 will have a higher proportion of high frequency sounds than will the sound issuing from the speaker 10.

As the high dwell of the cam 74 again engages the movable contact 26, that contact will again engage the movable contact 44; and the movable contact 42 will again move out of engagement with the stationary contact 40. At this time, and for a few further degrees of revolution of the output shaft of the motor 72, the movable contacts 52 and 70 will remain in engagement with each other and the movable contact 68 will remain out of engagement with the stationary contact 66. This means that some of the signals which are supplied to the terminals 14, and 16 will continue to pass through the speaker 12 and the capacitor 59 but that the rest of those signals will pass through the speaker 10 and the capacitor 24 rather than through that speaker and the parallel-connected resistor 34, inductor 36 and capacitor 38. All of this means that for this further short period of time when the high dwell of the cam 74 is holding both of the movable contacts 25 and 52 in their stressed positions, the signals corresponding to the high frequency sounds will be supplied to both of the speakers 10 and 12 without appreciable attenuation, while the signals which correspond to the low frequency sounds and which are supplied to both of those speakers will be attenuated.

As the cam 74 continues to rotate, the high dwell thereon will move out of engagement with the movable contact 52 and the low dwell thereon will move into register with that movable contact. Thereupon, the movable contact 52 will move to its un-stressed position; and at such time the movable contact 52 will be out of engagement with the movable contact 70 and the movable contact 68 will be in engagement with the stationary contact 66. Consequently, the sound issuing from the speaker 10 will again a higher proportion of high frequency sounds than will the sound issuing from the speaker 12; and the sound issuing from the speaker 12 will again have a higher proportion of low frequency sounds than will the sound issuing from the speaker 10.

It will thus be apparent that for about one-half of each revolution of the output shaft of the motor 72, the sound issuing from the speaker 10 will have a high proportion of high frequency sounds and will have a low proportion of low frequency sounds while the sound issuing from the speaker 12 will have a low proportion of high frequency sounds and will have a high proportion of low frequency sounds. For about the other one-half of each revolution of the output shaft of the motor 72, the sound issuing from the speaker 10 will have a low proportion of high frequency sounds and will have a high proportion of low frequency sounds while the sound issuing from the speaker 12 will have a high proportion of high frequency sounds and will have a low proportion of low frequency sounds. This means that during each revolution of the output shaft of the motor 72, the proportions of high frequency sounds and low frequency sounds will recurrently shift between the speakers 10 and 12; and this shifting produces an audible effect which enables many persons in a room to hear a simulation of substantially faithfully reproduced stereophonic sound.

The sound-reproducing device provided by the present invention can, where desired, be mounted in automobiles and other vehicles. Where that is done, the motor 72 will be a low voltage, direct current motor.

If desired, single pole cam-operated switches and multipole relays could be substituted for the two sets of multicontact switches shown in the drawing. Specifically, a single pole cam-operated switch and a relay with a set of normally-open contacts and a set of normally-closed contacts could be substituted for the contacts 26, 4t], 42 and 44. Similarly, another single pole cam-operated switch and another relay with a set of normally-open contacts and a set of normally-closed contacts could be substituted for the contacts 52, 66, 68 and 70.

If a lesser effect was acceptable, a cheap sound-reproducing device could be made by eliminating the junction 48, the capacitor 50, the resistor 54, the junction 56, the parallel-connected resistor 60, inductor 62 and capacitor 64, the junction 58, and the contacts 52, 66, 68 and 70. In such event, the conductor 46 would extend to the junction 43 and would directly and immediately connect the speaker 12 with that junction. With such an arrangement,

the signals supplied to the speaker 10 would alternately have a high proportion of high frequency sounds and a low proportion of low frequency sounds or a low proportion of high frequency sounds and a high proportion of low frequency sounds relative to the signals supplied to the speaker 12.

Whereas the drawing and accompanying description have shown and described one preferred embodiment of the present invention it should be apparent to those skilled in the art that various changes may be made in the form of the invention without affecting the scope thereof.

What I claim is:

1. A sound-reproducing device which can be connected 0 to a source of signals and which comprises:

(a) a speaker,

(b) a sound speaker,

(c) a capacitor and a set of contacts that can selectively connect the first said speaker to said source of signals,

((1) a second set of contacts and a parallel-connected inductor, capacitor and resistor that can selectively connect the first said speaker to said source of signals,

(e) a third set of contacts and a second capacitor that can selectively connect said second speaker to said source of signals,

(f) a fourth set of contacts and a second parallel-con nected inductor, capacitor and resistor that can selectively connect said second speaker to said source of signals, and

(g) a motor-driven cam that can actuate the first said,

said second, said third, and said fourth sets of contacts,

(h) said cam responding to operation of said motor to recurrently close the first said set of contacts and open said second set of contacts to enable signals to be supplied to the first said speaker through the first said capacitor and not through the first said parallel-connected inductor, capacitor and resistor,

(i) said cam responding to operation of said motor to recurrently close said third set of contacts and open said fourth set of contacts to enable signals to be supplied to said second speaker through said second capacitor and not through said second parallel-connected inductor, capacitor and resistor,

(j) said cam responding to operation of said motor to recurrently permit the first said set of contacts to open and said second set of contacts to close to enable signals to be supplied to the first said speaker through the first said parallel-connected inductor, capacitor and resistor and not through the first said capacitor,

(k) said cam responding to operation of said motor to recurrently permit said third set of contacts to open and said fourth set of contacts to close to enable signals to be supplied to said second speaker through said second parallel-connected inductor, capacitor and resistor and not through said second capacitor,

(1) said motor being a variable speed motor,

(m) said cam having a high dwell with an angular extent slightly greater than one hundred and eighty degrees,

(n) the first said and said second sets of contacts being approximately one hundred and eighty degrees from said third and said fourth sets of contacts,

(0) said cam responding to operation of said motor to recurrently close said third set of contacts and open said fourth set of contacts while the first said set of contacts is still closed and said second set of contacts is still open,

(p) said cam responding to operation of said motor to recurrently close the first said set of contacts and open said second set of contacts while said third set 9 of contacts is still closed and said fourth set of con tacts is still open. 2. A sound-reproducing device which can be connected to a source of signals and which comprises:

(a) a speaker,

(b) a second speaker,

(c) a capacitor and a set of contacts that can selectively connect the first said speaker to said source of signals,

(d) a second set of contacts and a parallel-connected inductor and capacitor that can selectively connect the first said speaker to said source of signals,

(e) a third set of contacts and a second capacitor that can selectively connect said second speaker to said source of signals,

(f) a fourth set of contacts and a second parallel-connected inductor and capacitor than can selectively connect said second speaker to said source of signals,

(g) a motor-driven cam that can actuate the first said,

said second, said third, and said fourth set of contacts,

(h) said cam responding to operation of said motor to recurrently close the first said set of contacts to enable signals to be supplied to the first said speaker through the first said capacitor and to recurrently open said second set of contacts to keep signals from being supplied to the first said speaker through the first said parallel-connected inductor and capacitor,

(i) said cam responding to operation of said motor to recurrently close said third set of contacts to enable signals to be supplied to said second speaker through said second capacitor and to recurrently open said fourth set of contacts to keep signals from being supplied to said second speaker through said second parallel-connected inductor and capacitor,

(j) said cam responding to operation of said motor to recurrently permit the first said set of contacts to open to keep signals from being supplied to the first said speaker through the first said capacitor and to recurrently permit said second set of contacts to close to enable signals to be supplied to the first said speaker through the first said parallel-connected inductor and capacitor,

(k) said cam responding to operation of said motor to recurrently permit said third set of contacts to open to keep signals from being supplied to said second speaker through said second capacitor and to recurrently permit said fourth set of contacts to close to enable signals to be supplied to said second speaker through said second parallel-connected inductor and capacitor,

(1) said cam responding to operation of said motor to recurrently close said first and fourth sets of contacts and to open said second and third sets of contacts,

(m) said cam responding to operation of said motor to recurrently close said second and third sets of contacts and to open said first and fourth sets of contacts.

3. A sound-reproducing device which can be connected to a source of signals and which comprises:

proportion of low frequency sounds or a 10W proportion of 'high frequency sounds and a high proportion of low frequency sounds,

(h) second contacts alternately connecting said second speaker to said source of signals through said second capacitor or through said second parallelconnected inductor and capacitor whereby the sound issuing from said second speaker will alternately have a high proportion of high frequency sounds and a low proportion of low frequency sounds or a low proportion of high frequency sounds and a high proportion of low frequency sounds,

(i) the first said and said second contacts recurrently connecting the first said speaker to a source of signals through the first said capacitor while also conmeeting said second speaker to said source of signals through said second parallel-connected inductor and capacitor,

(j the first said and said second contacts recurrently connecting said second speaker to a source of signals through said second capacitor While also connecting the first said speaker to said source of signals through the first said parallel-connected inductor and capacitor.

4. A sound-reproducing device which can be selectively connected to a monaural or stereophonic sound-reproducing device and which comprises:

(a) a terminal Which can be connected to the common terminal of a stereophonic sound-reproducing device or to one of the terminals of a monaural soundreproducing device,

'(b) a second terminal which can be connected to a second terminal of said stereophonic sound-reproducing device or to the other of the terminals of said vmonaural sound-reproducing device,

(0) a third terminal which can be connected to the third terminal of said stereophonic sound-reproducing device or to said other of said terminals of said monaural sound-reproducing device,

(d) aspeaker,

(e) a second speaker,

(f) a capacitor,

(g) a parallel-connected inductor and capacitor,

(h) a second capacitor,

(i) ad second parallel-connected inductor and capacitor,

(j) contacts alternately connecting the first said speaker to the first said and said second terminals through the first said capacitor or through the first said parallel-connected inductor and capacitor,

(k) second contacts alternately connecting said second speaker to the first said and said third terminals through said second capacitor or through said second parallel-connected inductor and capacitor,

(1) the first said and said second contacts connecting said source of signals to the first said speaker through the first said capacitor and to said second speaker through said second paralle -connected inductor and capacitor, and thereafter connecting said source of signals to said second speaker through said second capacitor and to the first said speaker through the first said parallel-connected inductor and capacitor.

5. A sound-reproducing device can be connected to a source of signals and which comprises:

(a) a speaker,

(b) a second speaker,

(c) a capacitor,

(d) a parallel-connected inductor and capacitor,

(e) contacts that selectively connect the first said speaker to said source of signals through said capacitor or through said parallel-connected inductor and capacitor,

(f) a second capacitor,

(g) a second parallel-connected inductor and capacitor,

and

(h) further contacts that selectively connect said second speaker to said source of signals through said second capacitor or through said second parallelconnected inductor and capacitor,

(i) the first said contacts alternately connecting the first said speaker to said source of signals through the first said capacitor or through the first said parallel-connected inductor and capacitor, whereby the sound issuing from the first said speaker will alternately have a high proportion of high frequency sounds and a low proportion of low frequency sounds or a low proportion of high frequency sounds and a high proportion of low frequency sounds,

(j) said second contacts alternately connecting said second speaker to said source of signals through said second capacitor or through said second parallelconnected inductor and capacitor whereby the sound issuing from said second speaker will alternately have a high proportion of high frequency sounds and a low proportion of low frequency sounds or a low proportion of high frequency sounds and a high proportion of low frequency sounds.

6. A sound-reproducing device which can be connected to a source of signals and which comprises:

(a) a speaker,

(b) a second speaker,

(c) a sub-circuit that is connectable to the first said speaker and to said source of signals to attenuate signals from said source of signals corresponding to low-frequency sounds while passing signals from said source of signals corresponding to high-frequency sounds without appreciable attenuation,

(d) a second sub-circuit that is connectable to the first said speaker and to said source of signals to attenuate signals from said source of signals corresponding to high-frequency sounds while passing signals from said source of signals corresponding to low-frequency sounds without appreciable attenuation,

(e) a third sub-circuit that is connectable to said second speaker and to said source of signals to attenuate signals from said source of signals corresponding to low-frequency sounds while passing signals from said source of signals corresponding to high-frequency sounds without appreciable attenuation,

(f) a fourth sub-circuit that is connectable to said second speaker and to said source of signals to attenuate signals from said source of signals corresponding to high-frequency sounds while passing signals from said source of signals corresponding to low-frequency sounds without appreciable attenuation,

(g) means selectively connecting the first said subcircuit to the first said speaker and to said source of signals and said fourth sub-circuit to said second speaker and to said source of signals, and

(h) means selectively connecting said second subcircuit to the first said speaker and to said source of signals and said third sub-circuit to said second speaker and to said source of signals.

7. A sound-reproducing device which can be connected to a source of signals and which comprises:

(a) a speaker,

(b) a second speaker,

(c) a sub-circuit that is connectable to the first said speaker and to said source of signals to attenuate signals from said source of signals corresponding to low-frequency sounds while passing signals from said source of signals corresponding to high-frequency sounds without appreciable attenuation,

(d) a second sub-circuit that is connectable to the first said speaker and to said source of signals to attenuate signals from said source of signals corresponding to high-frequency sounds while passing signals from said source of signals corresponding to low-frequency sounds without appreciable attenuation,

(e) whereby the signals from said source of signals supplied to the first said speaker can alternately have a high proportion of high frequency sounds and a low proportion of low frequency sounds or a low proportion of high frequency sounds and a high proportion of low frequency sounds,

(f) means that connects the first said sub-circuit to the first said speaker and the said source of signals and thereafter connects said second sub-circuit to the first said speaker and the said source of signals,

(g) further means that connects said second speaker to said source of signals, to enable said source of signals to supply signals to said second speaker,

(h) the first said means and the first said sub-circuit being adapted at times to cause signals supplied to the first said speaker by said source of signals to have a proportion of high frequency sounds which is higher than the proportion of high frequency sounds in the signals supplied to said second speaker by said source of signals and said further means,

(i) the first said means and said second sub-circuit being adapted at other times to cause signals supplied to the first said speaker by said source of signals to have a proportion of high frequency sounds which is lower than the proportion of high frequency sounds in the signals supplied to said second speaker by said source of signals and said further means,

(j) the first said means and said second sub-circuit being adapted at said other times to cause signals supplied to the first said speaker by said source of signals to have a proportion of low frequency sounds which is higher than the proportion of low frequency sounds in the signals supplied to said second speaker by said source of signals and said further means,

(k) the first said means and the first said sub-circuit being adapted at the first said times to cause signals supplied to the first said speaker by said source of signals to have a proportion of low frequency sounds which is lower than the proportion of low frequency sounds in the signals supplied to said second speaker by said source of signals and said further means.

References Cited by the Examiner UNITED STATES PATENTS 2,179,840 11/1939 Bucky 179-l.3 3,156,769 11/1964 MarkoWitZ 1791.3

KATHLEEN H. CLAFFY, Primary Examiner.

S. J. BOR, A. H. GESS, Assistant Examiners. 

1. A SOUND-REPRODUCING DEVICE WHICH CAN BE CONNECTED TO A SOURCE OF SIGNALS AND WHICH COMPRISES: (A) A SPEAKER, (B) A SOUND SPEAKER, (C) A CAPACITOR AND A SET OF CONTACTS THAT CAN SELECTIVELY CONNECT THE FIRST SAID SPEAKER TO SAID SOURCE OF SIGNALS, (D) A SECOND SET OF CONTACTS AND A PARALLEL-CONNECTED INDUCTOR, CAPACITOR AND RESISTOR THAT CAN SELECTIVELY CONNECTE THE FIRST SAID SPEAKER TO SAID SOURCE OF SIGNALS, (E) A THIRD SET OF CONTACTS AND A SECOND CAPACITOR THAT CAN SELECTIVELY CONNECT SAID SECOND SPEAKER TO SAID SOURCE OF SIGNALS, (F) A FOURTH SET OF CONTACTS AND A SECOND PARALLEL-CON NECTED INDUCTOR, CAPACITOR AND RESISTOR THAT CAN SELECTIVELY CONNECT SAID SECOND SPEAKER TO SAID SOURCE OF SIGNALS, AND (G) A MOTOR-DRIVEN CAM THAT CAN ACTUATE THE FIRST SAID, SAID SECOND, SAID THIRD, AND SAID FOURTH SETS OF CONTACTS, (H) SAID CAM RESPONDING TO OPERATION OF SAID MOTOR TO RECURRENTLY CLOSE THE FIRST SAID SET OF CONTACTS AND OPEN SAID SECOND SET OF CONTACTS TO ENABLE SIGNALS TO BE SUPPLIED TO THE FIRST SAID SPEAKER THROUGH THE FIRST SAID CAPACITOR AND NOT THROUGH THE FIRST SAID PARALLEL-CONNECTED INDUCTOR, CAPACITOR AND RESISTOR, (I) SAID CAM RESPONDING TO OPERATION OF SAID MOTOR TO RECURRENTLY CLOSE SAID THIRD SET OF CONTACTS AND OPEN SAID FOURTH SET OF CONTACTS TO ENABLE SIGNALS TO BE SUPPLIED TO SAID SECOND SPEAKER THROUGH SAID SECOND CAPACITOR AND NOT THROUGH SAID SECOND PARALLEL-CONNECTED INDUCTOR, CAPACITOR AND RESISTOR, (J) SAID CAM RESPONDING TO OPERATION OF SAID MOTOR TO RECURRENTLY PERMIT THE FIRST SAID SET OF CONTACTS TO OPEN AND SAID SECOND SET OF CONTACTS TO CLOSE TO ENABLE SIGNALS TO BE SUPPLIED TO THE FIRST SAID SPEAKER THROUGH THE FIRST SAID PARALLEL-CONNECTED INDUCTOR, CAPACITOR AND RESISTOR AND NOT THROUGH THE FIRST SAID CAPACITOR, (K) SAID CAM RESPONDING TO OPERATION OF SAID MOTOR TO RECURRENTLY PERMIT SAID THIRD SET OF CONTACTS TO OPEN AND SAID FOURTH SET OF CONTACTS TO CLOSE TO ENABLE SIGNALS TO BE SUPPLIED TO SAID SECOND SPEAKER THROUGH SAID SECOND PARALLEL-CONNECTED INDUCTOR, CAPACITOR AND RESISTOR AND NOT THROUGH SAID SECOND CAPACITOR, (L) SAID MOTOR BEING A VARIABLE SPEED MOTOR, (M) SAID CAM HAVING A HIGH DWELL WITH AN ANGULAR EXTENT SLIGHTLY GREATER THAN ONE HUNDRED AND EIGHTY DEGREES, (N) THE FIRST SAID AND SAID SECOND SETS OF CONTACTS BEING APPROXIMATELY ONE HUNDRED AND EIGHTY DEGREES FROM SAID THIRD AND SAID FOURTH SETS OF CONTACTS, (O) SAID CAM RESPONDING TO OPERATION OF SAID MOTOR TO RECURRENTLY CLOSE SAID THIRD SET OF CONTACTS AND OPEN SAID FOURTH SET OF CONTACTS WHILE THE FIRST SAID SET OF CONTACTS IS STILL CLOSED AND SAID SECOND SET OF CONTACTS IS STILL OPEN, (P) SAID CAM RESPONDING TO OPERATION OF SAID MOTOR TO RECURRENTLY CLOSE THE FIRST SAID SET OF CONTACTS AND OPEN SAID SECOND SET OF CONTACTS WHILE SAID THIRD SET OF CONTACTS IS STILL CLOSED AND SAID FOURTH SET OF CONTACTS IS STILL OPEN. 